Method for simulcrypting scrambled data to a plurality of conditional access devices

ABSTRACT

In accordance with one embodiment, a method for storing a normal scrambled digital program is provided. The method includes receiving a scrambled program, and receiving a plurality of access requirements. Each access requirement can descramble the scrambled program. The method also includes selecting at least one of the access requirements, and storing the scrambled program and the selected requirement.

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] The present invention relates to digital devices. Morespecifically, the present invention relates to a copy management systemand method for controlling the reproduction and recording of digitalcontent on and from at least one digital device.

[0003] 2. General Background

[0004] Analog communication systems are rapidly giving way to theirdigital counterparts. Digital television is currently scheduled to beavailable nationally to all consumers by the year 2002 and completely inplace by the year 2006. High-definition television (HDTV) broadcastshave already begun in most major cities on a limited basis. Similarly,the explosive growth of the Internet and the World Wide Web haveresulted in a correlative growth in the increase of downloadableaudio-visual files, such as MP3-formatted audio files, as well as othercontent.

[0005] Simultaneously with, and in part due to, this rapid move todigital communications system, there have been significant advances indigital recording devices. Digital versatile disk (DVD) recorders,digital VHS video cassette recorders (D-VHS VCR), CD-ROM recorders(e.g., CD-R and CD-RW), MP3 recording devices, and hard disk-basedrecording units are but merely representative of the digital recordingdevices that are capable of producing high quality recordings and copiesthereof, without the generational degradation (i.e., increaseddegradation between successive copies) known in the analog counterparts.The combination of movement towards digital communication systems anddigital recording devices poses a concern to content providers such asthe motion picture and music industries, who desire to prevent theunauthorized and uncontrolled copying of copyrighted, or otherwiseprotected, material.

[0006] In response, there is a movement to require service providers,such as terrestrial broadcast, cable and direct broadcast satellite(DBS) companies, and companies having Internet sites which providedownloadable content, to introduce protection schemes. Two such copyprotection systems have been proposed by the 5C group of the Data HidingSub Group (DHSG) (5C comprising representatives of Sony, Hitachi,Toshiba, Matsushita, and Intel) and the Data Transmission DiscussionGroup (DTDG), which are industry committee subgroups of the CopyProtection Technical Working Group (CPTWG). The CPTWG represents thecontent providers, computer and consumer electronic productmanufacturers.

[0007] The DTDG Digital Transmission Copy Protection (DTCP) proposal istargeted for protecting copy-protected digital content, which istransferred between digital devices connected via a digital transmissionmedium such as an IEEE 1394 serial bus. Device-based, the proposal usessymmetric key cryptographic techniques to encode components of acompliant device. This allows for the authentication of any digitaldevice prior to the transmission of the digital content in order todetermine whether the device is compliant. The digital content is itselfencoded prior to transmission so that unauthorized copying of thecontent will result in copy having an unintelligible format.

[0008] One method of encoding the content has been proposed by the DHSG,and is based on watermarking techniques. Although the main focus of theDHSG proposal has been for copy protection of digital movie and videocontent, particularly as applied to DVD systems, it is expected to beapplicable to the copy protection of any digital content distributedelectronically via digital broadcasts and networks. The watermarkingtechniques, which are invisible to the user, allow the incoming contentto be marked in a manner that makes it extremely difficult to discernprecisely how the content was encoded, and thus extremely difficult toremove or alter the watermark without damaging the content. The DHSG hasdetermined three primary cases of detection and control that such atechnology should accomplish: playback, record and generational copycontrol. It is anticipated that the watermarking technology will allowthe content provider to specify at least whether the content is “copynever,” “copy once,” and “copy free” content. “Copy never” is used tomark digital content to indicate that the content is not allowed to becopied, while “copy free” indicates that the content may be copiedfreely and which can be marked with additional information. This isdifferent than material that is never marked. Finally, “copy once” isused to indicate that the digital content is allowed to be copied onlyonce. As a copy is being made, the original “copy once” content and thenewly copied content are re-marked with “no more copy.” Of course, othertypes of copy management commands may limit the playing or reproductionof such digital content; for example, to a specific period of time,duration, or number of plays or viewings.

[0009] Thus, even today, the functionality of digital devices such asset-top boxes, digital televisions, digital audio players, and similarsuch digital devices extends beyond their historical role of conditionalaccess (CA), i.e., merely descrambling content to a CA-clear format forreal-time viewing and/or listening, and now include constraints andconditions on the recording and playback of such digital content. Forexample, currently, copying of scrambled content for subsequentdescrambling and viewing or listening may be permitted with theappropriate service/content provider authorization or key provided tothe digital device

[0010] A disadvantage of such digital devices is that do not allow thesimultaneous viewing of content in a CA descrambled format (hereinafterreferred to as “descrambled content”) and the recording of content in aCA-scrambled content (hereinafter referred to as “scrambled content”),both of which are typically copy-protected, using, for example, somesort of watermarking process, as proposed by the DHSG. Thus, the digitaldevices support either the viewing of descrambled content or therecording of such scrambled content, but not both. Additionally, inthose instances where the digital device is connected to other digitaldevices over a transmission medium via a digital interface, there mayalso be additional encoding at the digital interface prior to input intothe transmission medium; e.g., using the 5C-proposed copy-protectionscheme. In such cases, the viewable form, e.g., descrambled content,with “copy never” attributes would not be recordable by downstreamdevices. However, the non-viewable, or scrambled, content wouldtypically have “copy free” attributes. As the simultaneous viewing ofdescrambled content and the recording of scrambled content is notpossible under these scenarios, it is difficult to “time shift”copy-protected content and impossible to record a scrambled programwhile it is being viewed, even though such recording is for theviewer's/listener's sole entertainment at a later point in time. Bothare considered desirable by viewers, listeners and other consumers.

[0011] Therefore, in view of the interests of the aforementionedviewers, listeners and other consumers, it would be desirable to providea system that allows for the simultaneous viewing, listening or playingof descrambled content and recording of the scrambled content which alsoaddressed the concerns of the various content providers.

SUMMARY

[0012] In accordance with an embodiment of the present invention, amethod for storing a normal scrambled digital program is provided. Themethod includes receiving a scrambled program, and receiving a pluralityof access requirements. Each access requirement can descramble thescrambled program. The method also includes selecting at least one ofthe access requirements, and storing the scrambled program and theselected requirement.

BRIEF DESCRIPTION OF THE DRAWINGS

[0013] The present invention is illustrated by way of example and not byway of limitation in the figures of the accompanying drawings, in whichlike references indicate similar elements and in which:

[0014]FIG. 1 is a block diagram of an exemplary entertainment systemincluding one embodiment of a digital device;

[0015]FIG. 2 is a block diagram of one embodiment of a digital receiverof the digital device;

[0016]FIG. 3 is a block diagram of one embodiment of the conditionalaccess unit of the copy management system of the present invention;

[0017]FIG. 4 is a block diagram of an embodiment of the conditionalaccess unit of the system of the present invention; and,

[0018]FIG. 5 is a block diagram of an embodiment of the digital receiverof the digital device.

[0019]FIG. 6 is a block diagram of an embodiment of the digital receiverof the digital device.

[0020]FIGS. 7, 8, and 9 show embodiments of a filtering function.

[0021]FIG. 10 shows an embodiment of an apparatus including conditionalaccess units that can be simulcrypted.

[0022]FIG. 11 shows an embodiment of a method simulcrypted conditionalaccess unit.

[0023]FIG. 12 shows an embodiment of a method for simulcryptingscrambled data to a plurality of conditional access units.

[0024]FIG. 13 shows another embodiment of a method f-oir simulcryptingscrambled data to a plurality of conditional access units.

[0025]FIG. 14 shows an embodiment of a method for simulcrypting duringopportunistic bandwidth.

DETAILED DESCRIPTION

[0026]FIG. 1 is a block diagram of an entertainment system 100 includingone embodiment of the copy management system of the present invention.The entertainment system 100 includes a digital device 110 for receivinga digital bitstream including program data from one or more serviceproviders. Such service or content providers can include terrestrialbroadcasters, cable operators, direct broadcast satellite (DBS)companies, companies providing content for download via the Internet, orany similar such content and/or service provider. The program data mayinclude system information, entitlement control messages, entitlementmanagement messages, content, and other data, each of which will bedescribed briefly. System information may include information on programnames, time of broadcast, source, and a method of retrieval anddecoding, and well as copy management commands that provide digitalreceivers and other devices with information that will control how andwhen program data may be replayed, retransmitted and/or recorded. Thesecopy management commands may also be transmitted along with entitlementcontrol messages (ECM), which are generally used by the conditionalaccess unit to regulate access to a particular channel or service.Entitlement management messages (EMM) may be used to deliver privilegesto the digital receiver 111 such as rights, access parameters, anddescrambling keys. As known, a decryption key is generally a code thatis required to restore scrambled data, and may be a function of therights granted. Finally, content in the program data stream may includeaudio and video data, which may be in a scrambled or clear format.

[0027] The digital device 110 includes a digital receiver 111, whichprocesses th e incoming bitstream, extracts the program data therefrom,and provides the program data in a viewable format. The thus extractedprogram data is then provided to a decoding unit 112 for furtherprocessing, including separation of the system information from thecontent, as well as decoding, or decompressing, of the content to itsoriginal form. The digital receiver 111 also regulates access to theprogram data by other components on the entertainment system 100, andaccording to one embodiment of the present invention, supports thesimultaneous transmission of program data having content in adescrambled format (hereinafter referred to as “descrambled content”)and program data having content in a scrambled format (hereinafterreferred to as “scrambled content”).

[0028] According to one embodiment of the present invention, the digitaldevice 110 is a digital television set where the digital receiver 111 isa set-top box integrated therein, and the decoding unit 112 is an MPEG(Motion Picture Experts Group) decoder. The digital television set'sdisplay (not shown) is, according to this embodiment, integrated withinthe digital device 110. Alternatively, it will be appreciated that thedigital device 110 may include only the digital receiver 111 and/or thedecoder unit 112, with a display being external to the decoding device110. An example of this embodiment would be an integratedreceiver/decoder (IRD) such as a stand-alone set-top box which outputsNTSC, PAL or Y_(p)B_(p)R signals. All such embodiments are includedwithin the scope of the present invention.

[0029] Digital device 110 may be coupled to other components in theentertainment system 100 via a transmission medium 120. The transmissionmedium 120 operates to transmit control information and data includingprogram data between the digital device 110 and other components in theentertainment system 100. It will be appreciated that the entertainmentsystem 100 of FIG. 1 is merely an exemplary embodiment, and that otheranalog and/or digital components may be added or substituted for thecomponents briefly described hereinafter.

[0030] Referring to FIG. 1, the entertainment system 100 may include anaudio system 130 coupled to the transmission medium 120. The audiosystem 130 may include speakers and an audio player/recorder such as acompact disc player, a Sony MiniDisc® player, or other magneto-opticaldisc that may be used to play and/or record audio data. A digital VCR140, such as a D-VHS VCR, may also be coupled to the digital device 110and other components of the entertainment system 100 through thetransmission medium 120. As known, the digital VCR 140 may be used torecord analog or digital audio, video, and other data transmissions, andaccording to an embodiment of the present invention, may be used torecord program data received by the digital device 110 and transmittedto the digital VCR over transmission medium 120.

[0031] A hard disk recording unit 150 may also be coupled to digitaldevice 110 and other components via transmission medium 120. The harddisk recording unit 150 may be a personal computer system, a stand-alonehard disk recording unit, or other hard disk recording device capable ofrecording analog or digital audio, video and data transmissions. As withdigital VCR 140, according to one embodiment of the present invention,the hard disk recording unit 150, may be used to record program datareceived by the digital device 110 and transmitted to the hard diskrecording unit 150 over transmission medium 120.

[0032] Display 160 may include a high definition television display, amonitor or other device capable of processing digital video signals. Inan embodiment where the digital device 110 is a stand-alone set-top box,display 160 may be a digital television set.

[0033] Finally, a control unit 170 may be coupled to the transmissionmedium 120. The control unit 170 may be used to coordinate and controlthe operation of some or each of the components on the entertainmentsystem 100, as well and other electronic devices remotely coupledthereto.

[0034]FIG. 2 is a block diagram of one embodiment of the digitalreceiver 111 including the copy management system according to thepresent invention. The digital receiver 111 includes a centralprocessing unit (CPU) 210, which controls the overall operation of thedigital receiver 111, and determines the frequency in which a selectedchannel is broadcast or otherwise transmitted. This information is thentransmitted to a tuner 220, which then selects the appropriate frequencyof the terrestrial, cable, satellite, or Internet transmission in whichto receive the incoming digital bitstream, including program data. TheCPU 210 may also support a graphical user interface (GUI), such as anelectronic programming guide (EPG), the latter allowing a user tonavigate through various channels and program options to select adesired channel or program for viewing, listening, recording and thelike. The GUI may be displayed on either a display (not shown) ofdigital device 110 (e.g., where digital device 110 is a digitaltelevision set), or on display 160 (e.g., where digital device 110 is astand-alone set-top box).

[0035] Once the tuner 220 has selected the appropriate frequency, itamplifies the incoming digital bitstream, and provides the outputbitstream to a demodulator unit 230. The demodulator unit 230 receivesthe bitstream from the tuner 220 and demodulates the bitstream toprovide program data as originally transmitted. The type of demodulationeffected by the demodulator unit 230 will of course depend on the typeof transmission as well as the modulation process used in thetransmission process. For example, in the case of cable transmissionsand Internet transmissions received over cable modems, the demodulatorunit 230 may perform quadrature amplitude demodulation (QAD), while forsatellite broadcasts, quadrature phase shift key (QPSK) demodulationwill likely be required. Terrestrial broadcasts, will likely requirevestigial side band (VSB) demodulation. The present invention is notlimited to any one type of transmission and modulation/demodulationscheme, and other schemes are within the scope and spirit of the presentinvention. In addition to effecting the demodulation process,demodulator unit 230 may also perform error correction on the receivedbitstream.

[0036] The thus demodulated bitstream is now preferably provided to aconditional access unit 240. (That portion of the demodulated bitstreamthat is not encrypted may bypass the conditional access unit 240 and beprovided directly to the demultiplexer 250 as shown by the dashed linesin FIG. 2. This might also be the case where none of the bitstream needsdecrypting, and/or where there is no conditional access module). Theconditional access unit 240 generally performs key management anddecryption, as well as descrambling functions as follows.

[0037] Typically, if the CPU 210 determines that the program data in thedigital bitstream includes scrambled content, that program data isprovided to a conditional access unit 240. At this point the CPU 210 maytransmit packet identifier (PID) information to the conditional accessunit 240, such PID information informing the conditional access unit 240where in the program data the ECM may be found. The CPU 210 may insteadreceive the ECM and deliver it to the conditional access unit 240.Alternatively, the conditional access unit 240 may have demultiplexingcapabilities allowing it to directly obtain the location of the ECM fromthe bitstream itself. As discussed previously, the ECMs regulate auser's access to a particular channel or service, and determines theaccess rights that are needed to be held by a receiver 111 in order togrant access. The ECMs may also be used to deliver a decrypting ordescrambling key or to deliver information (e.g., an algorithm) as tohow to derive a key that may be used to descramble scrambled content.Using such key or information regarding derivation of such key, theconditional access unit 240 may descramble the content contained in theprogram data. Alternatively, the conditional access unit may provide thekey to the demultiplexer 250 which will perform the descrambling.

[0038] Importantly, although the conditional access unit 240 is shown asan integral, or embedded, in that both the descrambling and decryptingfunctions are effected internally in receiver 111, the conditionalaccess unit may also split or external. An external conditional accessunit descrambles the program data content and decrypts the keysexternally; e.g., as is the case with the National Renewable SecuritySystem (NRSS) conditional access modules. In a split conditional accessunit, the program data content is descrambled within the digitalreceiver 111, while the key decryption is completed externally, e.g.,via a “smart card.” All of these systems are intended to be within thespirit and scope of the present invention.

[0039] Once the conditional access unit 240 descrambles the program datacontent, the program data is input to demultiplexer unit 250, whichseparates the system information from the content in the program data.According to an embodiment of the demultiplexer unit 250, thedemultiplexer unit 250 parses the program data for PIDs that areassociated with system information, audio information and videoinformation, and then transmits the system information to the CPU 210and the audio and video information to the decoder unit 112. Inaccordance with one embodiment of the present invention, a digitalinterface unit 260 is coupled to the conditional access unit 240.Operation of this unit, which allows the receiver 111 to communicatewith other digital components in the entertainment system 100, will bediscussed at a later point.

[0040] The CPU 210, tuner 220, demodulator unit 230, conditional accessunit 240, demultiplexer unit 250, and digital interface unit 260 may beimplemented using any known technique or circuitry. In one embodiment ofthe present invention, the CPU 210, tuner 220, demodulator unit 230,demultiplexer unit 250, and digital interface unit 260 all reside in asingle housing, while the conditional access unit 240 resides in anexternal NRSS conditional access module (as discussed above).Alternatively, the conditional access unit can take the form factor of aPersonal Computer Memory Card International Association (PCMCIA) Type IIcard or a smart card.

[0041]FIG. 3 shows a block diagram of one embodiment of the conditionalaccess unit 240 of the copy management system of the present invention.The conditional access unit 240 includes a processor unit 330, whichreceives the demodulated program data from the demodulator unit 230 andobtains PID information identifying where ECMs may be found in theprogram data. Again, this packet identifier information may be providedby the CPU 210 or obtained directly from the bitstream by theconditional access unit 240 itself. It is also possible for the CPU 210to deliver ECMs to the conditional access unit 240.

[0042] In one embodiment of the present invention, the processor unit330 processes the ECMs and derives a key for descrambling the content.The processor unit 330 then outputs program data and the key to adescrambler unit 340 over line, pin or set of pins 335 (hereinafter,“line 335”). The descrambler unit 340 receives the key and the programdata off line 335 and processes the program data, including descramblingor decrypting the program data content with the key. The descramblerunit 340 then transmits the program data with the now clear content overline, pin or set of pins 346 (hereinafter, “line 346”) to thedemultiplexer unit 250 (FIG. 2), and then to the decoding unit 112, andfinally for display and viewing by a user.

[0043] The descrambler unit 340 also transmits the program data with thenow clear content over line, pin or set of pins 345 (hereinafter, “line345”) to a re-scrambler unit 350. The re-scrambler unit 350 receives theprogram data and processes the data, including re-scrambling the clearcontent. Re-scrambling can use a similar algorithm as used in thedescrambling process. For example, if DES could be used for both thedescrambling and re-scrambling processes.

[0044] (It will be appreciated that although for ease of understanding,the processor unit 330, the descrambler unit 340, and the re-scramblerunit 350 are shown as separate elements in FIG. 3, these elements may beintegrated in one device, or may be implemented using any knowncircuitry or technique).

[0045] The re-scrambler unit 350 may re-scramble the content in any oneof several ways. For example, in one embodiment of the copy managementsystem of the present invention, it may re-scramble the content usingthe ECMs originally transmitted in the received bitstream and receivedin receiver 111. Alternatively, separate re-scrambling keys may betransmitted in the original bitstream in separate ECMs and extracted bythe re-scrambler unit 350 from the program data received from thedescrambler unit 340. In another embodiment of the copy managementsystem of the present invention, the re-scrambler unit 350 may haveencrypting or encoding capabilities, allowing it to re-scramble thecontent using a local key which may be unique to receiver 111. Such akey would not be delivered using an ECM, but could be delivered to there-scrambler unit 350 using an EMM. Alternatively, the key could be anon-changeable key which has been created at the time of manufacture ofthe re-scrambler unit.

[0046] In yet another embodiment of the present invention, control wordsmay be used in addition to keys. In such embodiment, the control wordsare first scrambled using a key, and then are inserted into thebitstream program data prior to transmission. Under this method, inorder to descramble the content in the program data, the control accessunit 240 must first derive the key (using any of the aforementionedmethods) and then use the derived key to descramble the control words.The descrambled control words are then applied to descramble thecontent. This method gives added flexibility and security in thetransmission, particularly in the case where a local key is used (i.e.,located in the receiver 111), in that the control words (and thus accessrights) may be changed periodically without requiring a change of thelocal key. Using this method, the re-scrambler unit 350 may scramble thecontent using one of several methods. The re-scrambler unit 350 may usethe originally transmitted control words and key to re-scramble thecontrol words. Alternatively, the re-scrambler unit 350 may use localcontrol words and keys that are unique to the receiver 111. It will beappreciated to those skilled in the art that any one of theaforementioned methods of scrambling and descrambling may be used aloneor in combination, and these and other similar methods are intended tobe within the scope and spirit of the present invention.

[0047] Once the content is re-scrambled, the program data including there-scrambled content is transmitted over line, pin or set of pins 355(hereinafter, “line 355”). In one embodiment of the present invention,the re-scrambled program data is output over digital interface unit 260,as shown in FIG. 2. The digital interface unit 260 encodes this programdata with copy management commands that indicate that the program datais “copy free.” The digital interface unit 260 interfaces with thecomponents on the transmission medium 120 (shown in FIG. 1) to determinewhich components are authorized to decode the encoded program data, andthen transmits a key to the authorized components for decoding theencoded program data. According to one embodiment of the entertainmentsystem 100, the digital interface unit 260 initiates an authenticationprocess that identifies devices that are authorized to decode encodedprogram data, and then encodes program data transmitted on the IEEE 1394transmission medium using the DTDG's DTCP encoding scheme. It will beappreciated, however, that other encoding schemes may be implementedwithout detracting from the spirit and scope of the invention.

[0048] Thus, as line 346 transmits the clear content to thedemultiplexer unit 250 for display on a display which is either integralwith, or directly connected to, digital device 110, and line 345 carriesthe re-scrambled content over transmission medium 120 for recording onone or more of any of several components connected to the transmissionmedium 120, the conditional access unit 240 allows the user tosimultaneously view a program in the clear while recording the scrambledversion. It will be appreciated that, under this embodiment, the contentprovider can control when and if the user can copy or even view thecontent again given that the re-scrambled stream which is output overline 345 must be descrambled with the appropriate keys and/or controlwords before viewing, and thus must be processed by the conditionalaccess unit 240.

[0049] An alternate embodiment of the conditional access unit 240 of thecopy management system of the present invention is described withreference to FIG. 4. In this embodiment, the conditional access unit 240includes a processor unit 330 similar to that described in FIG. 3. Theprocessor unit 330 also outputs program data which may include scrambledcontent over a line, pin, or set of pins 335 (hereinafter, “line 335”)to a descrambler unit 340. Descrambler unit 340 is also similar to thedescrambler unit 340 of the embodiment of FIG. 3.

[0050] At this point, the descrambler unit outputs program data withclear content to either the demultiplexer unit 250 or to the digitalinterface unit 260 via line 345. The conditional access unit 240 alsoincludes a line, pin, or set of pins 436 (hereinafter, “line 436”)coupled to line 335 which bypasses the descrambling unit 340 and whichtransmitting program data, possibly including scrambled content, to thedigital interface unit 260.

[0051] As with the embodiment disclosed in FIG. 3, the conditionalaccess unit 240 of FIG. 4 provides two bitstreams of program data; line345 carries program data including clear content, while line 436 carriesprogram data including scrambled content. Thus, as line 345 transmitsthe clear content to the demultiplexer unit 250 for display on a displaywhich is either integral with, or directly connected to, digital device110, and line 436 provides the scrambled content over transmissionmedium 120 via digital interface unit 260 for recording on one or moreof any of several components connected to transmission medium 120, theconditional access unit 240 of the embodiment of FIG. 4 also allows theuser to simultaneously view a program in the clear, while recording thescrambled version. As with the embodiment of FIG. 3, a content providercan control when and if a user can copy or view again copy-protectedcontent.

[0052] It is expected that there will be multiple content and serviceproviders as well as multiple manufacturers of digital devices such asdigital device 110. As a result, it is envisioned that there may becertain instances where the embodiments of conditional access unit 240as shown in FIGS. 3 and 4 are not available. For example, a content orservice provider may desire that the copy management system of thepresent invention be implemented in any digital device 110 which isauthorized to receive such content or service, without regard to themanufacturer or particular design constraints of the digital device 110.Furthermore, in instances where either the content provider or devicemanufacturer wishes to implement the copy management system of thepresent invention on devices which may already have a conditional accesssystem implemented, access to the implemented conditional access systemto add the copy management system of the present invention is likely tobe limited and/or costly. For example, addition of the re-scramblingunit 350 of the embodiment of the conditional access unit of FIG. 3 maynot be possible, nor may the availability of an additional line 436 forproviding scrambled content (embodiment of the conditional access unitof FIG. 4). It may be desirable and/or necessary in these and otherinstances to implement a separate conditional access unit.

[0053] As seen in FIG. 5, an alternate embodiment of the digitalreceiver 111 having the copy management system of the present inventionincludes an additional conditional access unit 540. Although theconditional access unit 540 may be built into the digital receiver 111,it is expected that digital receiver will have an expansion slot, suchas a PCMCIA slot or Universal Services Bus (USB) slot to receive a cardor device which includes the conditional access unit 540. As with theembodiment of FIG. 2, the digital receiver 111 of this embodimentincludes a CPU 210, a tuner 220, demodulator unit 230, a conditionalaccess unit 240, a demultiplexing unit 230, and a digital interface unit260. In addition to these elements, the digital receiver 111 of FIG. 4includes a second conditional access unit 540, the operation of whichwill be now described.

[0054] Conditional access unit 540 receives an output bitstreamincluding program data having clear content from first conditionalaccess unit 240, and re-scrambles the data in response to controlcommands received from CPU 210. Conditional access unit 540 mayre-scramble the program data content using the ECMs transmitted in theoriginal bitstream received in digital receiver 111 or with a keytransmitted by the conditional access unit 240. Alternatively,conditional access unit 540 may use its own unique, local key. If thecontent was originally scrambled using control words in addition tokeys, the conditional access unit 540 may use the originally transmittedcontrol key to scramble the control words and use the originallytransmitted control words to scramble the program data content. It mayalso use its own local control words and key to scramble the key andcontent, respectively. It will be appreciated to those skilled in theart that any one of the aforementioned methods of scrambling may be usedalone or in combination, and these and other similar methods areintended to be within the scope and spirit of the present invention. Itwill also be appreciated that conditional access unit 540 also operatesin a manner similar to that of re-scrambling unit 350 of the conditionalaccess unit 240 of FIG. 3, however, again, access to the originalconditional access unit 240 is not required in this embodiment.

[0055] Once the program data content is re-scrambled, conditional accessunit 540 transmits the program data to digital interface unit 260, whereit is encoded with copy management commands. Thereafter, the programdata may be provided over transmission medium 120 to any componentsconnected thereto for recording. Thus, according to this embodiment ofthe digital receiver 111, one bitstream including program data havingclear content is provided to demultiplexer unit 250 and then to decodingunit 112 (FIG. 1) for display and viewing by a user, while a secondbitstream including program data having scrambled content is availablefor recording by any component connected to transmission medium 120. Aswith the previous embodiments, a content or service provider can controlwhen and if a user can copy or view again content which iscopy-protected.

[0056] Some digital devices 110 may include an NRSS copy protectionsystem having a detachable NRSS module. In instances where a detachableNRSS module is used, it is desirable to take advantage of the scrambledbitstream coming from the NRSS module. As seen in FIG. 6, yet anotherembodiment of a digital receiver 111 is shown which includes an NRSScopy protection system having a detachable NRSS module 640 and a DES ECBcopy protection chip 642. In this embodiment, the bitstream is providedfrom demodulator 230 to the NRSS module which is detachably connected tothe digital device 110. Scrambled output from NRSS module 640 is“tapped” outside of the digital device 110 prior to the bitstream'sre-entry into the digital device 110 and is provided to the digitalinterface 260 where it is preferably marked as “copy free” and thentransmitted over the transmission medium 120. A second scrambled streamis provided to the DES ECB copy protection chip 642 for descrambling.One descrambled stream is then provided to the de-multiplexer unit 250,while a second descrambled stream is provided to the digital interface260 where it is preferably marked as “copy never” and then transmittedover the transmission medium 120. Again, in such embodiment, a contentor service provider can control when and if a user can copy or viewagain content which is copy-protected.

[0057] The content of a digital program may be transmitted in scrambledform. In order for a conditional access unit to recover the scrambledcontent and permit a person to view the content in clear form, the unitmust have the necessary access requirements associated with thescrambled content. An access requirement includes a message thatdescribes the features that the conditional access unit must have inorder to decode the scrambled content. For example, a certain key may beneeded to view the content. Alternatively, a service tag associated witha given content provider may be required. Technical requirements such asa particular descrambling method may also be required and included as apart of the access requirements. The access requirements associated witha particular program may be transmitted to a conditional access unitalong with the program.

[0058] When a scrambled program is received by a conditional accessunit, the access requirements for the program are compared to theentitlements that the conditional access unit actually has. In order forthe conditional access unit to display the scrambled content in clearform, the access requirements for the program must match theentitlements of the conditional access unit. The entitlements may statethat the conditional access unit is entitled to view content from agiven service provider such as HBO, for example. The entitlements mayalso include one or more keys needed to descramble the content. Theentitlements also may define the time periods for which the conditionalaccess unit may descramble programs. The access requirements andentitlements thus form a part of the access control system to determinewhether a decoder is authorized to view a particular program.

[0059] The access requirements and entitlements can provide consumerswith a variety of choices for paying for the content and gaining accessto the scrambled content. These choices may include pay per play (PPP),pay per view (PPV), impulse pay per view (IPPV), time based historical,pay per time (PPT), repurchase of copy never movies, personalscrambling, and regional pay per view. Impulse pay per view is a featurewhich allows purchase of pay per view movies through credit that hasbeen previously downloaded into the set top box. Purchase records may bestored and forwarded by phone to a billing center. Time based historicalallows access to content that was delivered during a past time period,such as March through December, 1997, for example. The accessrequirements and entitlements can also provide consumers with differentoptions for storing the scrambled content.

[0060] These options may be selected by choosing one of a number CAdescriptors that have been included in the Service Information (SI)provided by the Service Provider. A terrestrial broadcaster may use CAdescriptors defined by an organization such as the ATSC. A cable systemoperator may use descriptors defined by the Society of CableTelecommunication Engineers (SCTE). By choosing a CA descriptor, forexample the MPAA approved DVD movie standard, a consumer can store thecontent to a writeable DVD. Included in that content may be theencrypted manufacturer keys needed to descramble that content. Themanufacturer keys may be delivered in a PID called out by the CA ProgramMap Table (PMT). The keys may be stored on the DVD. On playback in a DVDplayer, the proper manufacturer key for the particular manufacturer ofthe DVD player can be selected, and the content descrambled accordingly.For example, choosing the DIVX descriptor, allows the storing of contentin DIVX format. Similar to DVD, the CAT PID in the CA PMT may select thekeys used with the content. A DIVX player may access the content as itnormally would access packaged content.

[0061] These storage options are available even as realtime descramblingoptions are available. A consumer may decide which of the operations heor she wishes to perform. Note that with realtime descrambling options,a CAT may call out a PID where an EMM may be obtained. However, in theDVD and DIVX examples, for instance, EMMs may not be delivered with thecontent that way. They may be embedded in the player and/or delivered byphone.

[0062] The program as delivered over the air is conditional accessscrambled. The scrambled content may be delivered along with a pluralityof access requirements, including pay per view, for example. Theconditional access unit can descramble the content for real-timeviewing. However, the content may have copy generation management systeminformation which marks the content as copy never. This means that aclear version of the content may not be recorded. A scrambled version ofthe content can be treated as copy free. In other words, the scrambledcontent can be recorded in a digital storage medium for later retrieval.

[0063] The access requirements may be delivered to the conditionalaccess unit using packet identifiers (PIDs). Each PID may contain theaccess requirements associated with a given service or feature. Forexample, FIG. 7 shows that PID 10 contains access requirements for a payper time feature. Thus, the content that is delivered to a conditionalaccess unit may also include a large number of PIDs, thus enablingspecial revenue features, technical features, or other special featuresto be performed locally.

[0064] Before receiving the content, the customer may be given a numberof choices for gaining access to the content that is going to be storedto media. The customer may be required to purchase the right to accessand view the content. Therefore, if the customer wants to record thecontent for later retrieval and viewing, the access requirements thatthe customer bought also need to be stored with the content.

[0065] When a digital program is recorded, the access requirementsneeded to view the program may also be recorded along with the program.The access criteria can be delivered to the conditional access device inpacket identifiers (PIDs). FIG. 7 shows an example of several PIDs thatmay be delivered to a conditional access device. PIDs 8 and 9 are forthe scrambled audio and video content. PIDs 10, 11, 12 and 13 point tothe entitlement control messages for several methods of obtaining theaccess requirements for the scrambled program content. For example, theuser may wish to pay for the content on a pay-per-time basis.

[0066] PID 10, which contains the access requirements for pay-per-time,is allowed to pass through the PID filtering function and is recorded inthe storage device. The other access requirements, which representalternative methods of paying for the content, do not pass through thePID filtering function and are thus squelched. The filtering functionmay be performed by the decoder 250 of the conditional access device.

[0067] Recording only the access requirements that the customer hasbought provides several advantages. Recording the scrambled contentlocally enables the special revenue features such as PPV, PPT, anddelayed IPPV, for example. A large number of PIDs may be delivered tothe conditional access unit to enable these special features. Byrecording only the PID or PIDs for the service that the customerdesires, the storage requirements are reduced. Also, when the customerplays back the content, it would be confusing to the customer to displaythe payment options again, after the customer has already selected oneoption. After a customer has decided to view a program as pay per time,for example, the customer should not be able to access the content anyother way. This prevents confusion to the customer. The conditionalaccess system is able to process the stream prior to being recorded. Theconditional access system can mark the content on the media in order tofacilitate future retrieval and access, which allows for a customizationof the access rights.

[0068] The security of the system is also improved by the filteringfunction shown in FIG. 7. Recording only one set of access requirementssecurely prevents hackers from tampering with the conditional accessfeatures, because the complexity of the system is reduced. Recording oneset of requirements can be done securely. Simplified access using onlyone option, such as PPV, for example, simplifies the processing, thecryptography, and reduces protocol problems, because only one set ofaccess requirements has to be tracked.

[0069]FIG. 8 shows an alternative embodiment that includes regional payper view. Customers in different regions may have different accessrequirements for a program, such as different costs. If a person inregion 1 wishes to record the scrambled content and view it at a latertime, only the access requirements for region 1 pass through the filterand are recorded in the digital storage medium.

[0070] Thus, an advantage of recording only the access requirements forone region is that it is much simpler than putting all access rights forall regions in one ECM. Thus, the system is enabled to offer differentcosts to different regions. Another advantage is the reduced storagerequirements, which is much less than recording all of the regions, andrecording information that does not concern a given customer. This way acustomer can listen to what is needed and simplify the filtering,because the PID filtering function is based on one region.

[0071]FIG. 9 shows an alternative embodiment that includes personalscrambling features to be delivered to the conditional access device inPIDs. The personal scrambling features allow a customer to customize thespecial features.

[0072] The PIDs can be used to enable a home entertainment system toprovide simulcrypting for two or more conditional access units. Oneconditional access unit 240 may be permanently embedded in the programviewing unit 111. For example, a digital television may contain aconditional access unit inside of the television. The conditional accessunit inside of such a system may not be upgraded without replacing thehost device. Also, the conditional access unit 240 may be enabled tofunction with content delivered by a service provider. The user canreceive content from a service provider by paying a monthly subscriptionfee, for example. The service provider may not be concerned withproviding copy control of the content that is delivered to the user. Theservice provider may only care about receiving a subscription fee anddelivering content to the user. Therefore, a relatively simpleconditional access device can provide real time access to contentdelivered to the program viewing unit from the service provider.

[0073] However, the provider or owner of the content that is deliveredby the service provider may provide copy control protection to thedelivered content, so that the content may be descrambled and viewed inreal time but may not be copied in a descrambled format. The contentprovider, or the viewer, or both, may want a conditional access unitthat is able to record the program content and descramble it at a latertime. Features such as pay per play and pay per time, which arediscussed above, can permit a user to record the content and view it ata later date while protecting the interests of the owner of the content.If the conditional access unit in the program viewing unit does not havethe ability to handle features such as pay per view, then a secondconditional access unit may be added.

[0074] The second conditional access unit 180 can be attached to thehome entertainment system, as shown in FIG. 1. The second conditionalaccess unit 180 can be a device capable of enabling features such as payper view to be provided to a user of the home entertainment system. Thesecond conditional access unit may use an interface, such as 1394interface, for example, so that it does not have to be attached to apre-designated slot in the program data receiver, as shown in FIG. 10.

[0075] The program data receiver may function as a controller for 1394devices in the home entertainment network. The receiver can direct thecontent to be stored on 1394 storage devices such as a 1394 VCR or harddisk, for example, when a user wishes to view the content, the contentcan be retrieved from memory and delivered to the second conditionalaccess unit on the 1394 bus, as shown in FIG. 11. The second conditionalaccess unit then descrambles the content so that it can be displayed inclear format. In one embodiment, the second conditional access unit canreceive a key to descramble the content using a telephone line.

[0076] In one embodiment, the content is delivered to the program datareceiver in a scrambled format. A packet identifier (PID) that containsthe access requirements, including a key, needed to descramble thecontent and view it using the first conditional access unit is deliveredto the program data receiver. A second packet identifier that containsthe access requirements for descrambling the scrambled data by thesecond conditional access device is also delivered. The second PID maybe delivered along with the first PID. Alternatively, the second PID maybe delivered at a later time. Additional packet identifiers, forenabling various features of the home entertainment system, may also beprovided as discussed above.

[0077] The first conditional access unit and its associated PID candescramble the content and provide the clear content to a display. Thescrambled data may be stored in memory. The second PID may also bestored in memory. The second conditional access unit can descramble thecontent using the second PID. Because the second conditional access unitcan use one or more PIDs that enable the scrambled content to be storedto a digital memory, retrieved from memory, and descrambled at a latertime, the user can create a home library of stored content. Furthermore,the home entertainment system can be upgraded and additional featurescan be enabled by the second conditional access unit without replacingthe program viewing unit.

[0078] In one embodiment, FIG. 12 shows a method for descrambling thescrambled data that includes receiving the scrambled data in a programdata receiver, step 1210. A first access key to descramble the scrambleddata, and a second access key to descramble the scrambled data are alsoreceived 1220. Each access key may be contained in one or more PIDs. Thefirst access key is associated with a first conditional access unit, andthe second access key is associated with a second conditional accessunit.

[0079] The scrambled data can be descrambled in real time, for example,using the first conditional access unit and the first key 1230. Then,the scrambled data and the second access key are recorded in a computerreadable memory 1240. The second access key and the scrambled data canbe retrieved from the memory 1250, and the scrambled data can bedescrambled using the second conditional access unit and the secondaccess key 1260.

[0080] The second access key permits the second conditional access unitto descramble the scrambled data during a time period including apresent time period and a future time period. Alternatively, the firstconditional access unit can descramble the scrambled data during a firstperiod, and the second conditional access unit can descramble thescrambled data during a second period that is different from the firstperiod.

[0081] In an alternative embodiment, FIG. 13 shows a method for copymanagement for controlling the recording and reproduction of digitalcontent that includes receiving a digital bitstream including programdata 1310. The program data may include system information and thedigital content in a scrambled format. The digital content in ascrambled format is descrambled to provide a first output including saiddigital content in a descrambled format 1320. A second output includingsaid digital content in the scrambled format is provided 1330. The firstoutput including said digital content in the descrambled format and thesecond output including said digital content in the scrambled format areoutput 1340. A plurality of access requirements are received 1350,wherein each access requirement can descramble the program data. Atleast one of the access requirements is selected 1360. The scrambledprogram data and the selected at least one access requirement are stored1370.

[0082] The method may include receiving and recording said digitalcontent of said second output in a scrambled format. The method mayinclude demultiplexing the digital content from the program data, anddecompressing the digital content in a descrambled format to adecompressed state 1380. The decompressing may be executed in an MPEGdecoder. The digital content may be content contained in digitaltelevision transmissions. Alternatively, the digital content may becontent downloaded from the Internet.

[0083] The descrambling may be carried out in a first conditional accessunit. The stored scrambled program data and the stored accessrequirement can be retrieved. Then, the retrieved scrambled program canbe descrambled using the access requirement in a second conditionalaccess unit. The descrambling step may include extracting a descramblingkey included in the program data, and applying said descrambling key tosaid digital content in a scrambled format to provide said digitalcontent in a descrambled format.

[0084] The method of receiving scrambled data, receiving a first accesskey to descramble the scrambled data using a first conditional accessunit, and receiving a second access key to descramble the scrambled datausing a second conditional access unit is a method of simulcrypting. Twodifferent conditional access units are enabled to descramble thescrambled data. In one embodiment, two different PIDs, received alongwith the scrambled content, enable the two conditional access units todescramble the data. One conditional access unit may descramble the databefore it is recorded, to provide real-time viewing. The otherconditional access unit may descramble the data after it is recorded andsubsequently retrieved from memory, to provide time-shiftedsimulcrypting, or viewing at a later time.

[0085] In one embodiment, FIG. 14 shows that two different programs canbe delivered to the program viewing unit simultaneously 1410. A firstprogram may be sent to the viewing unit along with a PID to be used bythe first conditional access unit to descramble the first program inreal time, step 1420. A second program may be sent using theopportunistic bandwidth that is available, step 1430. Because thebandwidth needed to send the first program fluctuates, the secondprogram can be sent in non-real time by taking advantage of thisfluctuating bandwidth. Thus, the second program, along with a PID forenabling the second conditional access device to descramble the secondprogram, can be trickled into digital memory and viewed at a later time,step 1440.

[0086] In the foregoing description, the invention is described withreference to specific exemplary embodiments thereof. It will, however,be evident that various modifications and changes may be made theretowithout departing from the broader spirit and scope of the presentinvention as set forth in the appended claims. The specification anddrawings are accordingly to be regarded in an illustrative rather thanin a restrictive sense.

What is claimed is:
 1. A method comprising: receiving scrambled data;receiving a first access key to descramble the scrambled data; receivinga second access key to descramble the scrambled data.
 2. The method ofclaim 1 wherein the first access key is associated with a firstconditional access unit.
 3. The method of claim 2 wherein the secondaccess key is associated with a second conditional access unit.
 4. Themethod of claim 3 further comprising descrambling the scrambled datausing the first conditional access unit and the first key.
 5. The methodof claim 4 further comprising recording the scrambled data and thesecond access key in a computer readable memory.
 6. The method of claim5 further comprising retrieving the second access key and the scrambleddata from the memory.
 7. The method of claim 6 further comprisingdescrambling the scrambled data using the second conditional access unitand the second access key.
 8. The method of claim 7 wherein the secondaccess key permits the second conditional access unit to descramble thescrambled data during a time period including a present time period anda future time period.
 9. The method of claim 7 wherein the firstconditional access unit descrambles the scrambled data during a firstperiod, and the second conditional access unit descrambles the scrambleddata during a second period that is different from the first period. 10.A copy management method for controlling the recording and reproductionof digital content comprising: receiving a digital bitstream includingprogram data, said program data including system information and saiddigital content in a scrambled format; descrambling said digital contentin a scrambled format to provide a first output including said digitalcontent in a descrambled format; providing a second output includingsaid digital content in the scrambled format; outputting said firstoutput including said digital content in the descrambled format and thesecond output including said digital content in the scrambled format;receiving a plurality of access requirements, wherein each accessrequirement can descramble the program data; selecting at least one ofthe access requirements; storing the scrambled program data and theselected at least one access requirement.
 11. The copy management methodof claim 10, further comprising receiving and recording said digitalcontent of said second output in a scrambled format.
 12. The copymanagement method of claim 10, further comprising: demultiplexing saiddigital content from said program data; and decompressing said digitalcontent in a descrambled format to a decompressed state.
 13. The copymanagement method of claim 10, wherein said decompressing is executed inan MPEG decoder.
 14. The copy management method of claim 10, whereinsaid digital content is content contained in digital televisiontransmissions.
 15. The copy management method of claim 10, wherein saiddigital content is content downloaded from the Internet.
 16. The copymanagement method of claim 10, wherein said descrambling is carried outin a first conditional access unit.
 17. The copy management method ofclaim 16, further comprising: retrieving the stored scrambled programdata and the stored access requirement; descrambling the scrambledprogram using the access requirement in a second conditional accessunit.
 18. The copy management method of claim 10, wherein saiddescrambling comprises: extracting a descrambling key included in saidprogram data; and applying said descrambling key to said digital contentin a scrambled format to provide said digital content in a descrambledformat.
 19. An apparatus comprising: a receiver to receive scrambleddata; a first descrambler to use a first access key to descramble thescrambled data; a second descrambler to use a second access key todescramble the scrambled data.
 20. The apparatus of claim 19 wherein thefirst access key is associated with a first conditional access unit. 21.The apparatus of claim 20 wherein the second access key is associatedwith a second conditional access unit.
 22. The apparatus of claim 21wherein the first descrambler can descramble the scrambled data usingthe first conditional access unit and the first key.
 23. The apparatusof claim 22 further comprising a recorder to record the scrambled dataand the second access key in a computer readable memory.
 24. Theapparatus of claim 23 further comprising a retriever to retrieve thesecond access key and the scrambled data from the memory.
 25. Theapparatus of claim 24 wherein the second descrambler can descramble thescrambled data using the second conditional access unit and the secondaccess key.
 26. The apparatus of claim 25 wherein the second access keypermits the second conditional access unit to descramble the scrambleddata during a time period including a present time period and a futuretime period.
 27. The apparatus of claim 25 wherein the first conditionalaccess unit descrambles the scrambled data during a first period, andthe second conditional access unit descrambles the scrambled data duringa second period that is different from the first period.
 28. A copymanagement apparatus for controlling the recording and reproduction ofdigital content comprising: a receiver to receive a digital bitstreamincluding program data, said program data including system informationand said digital content in a scrambled format; a descrambler todescramble said digital content in a scrambled format to provide a firstoutput including said digital content in a descrambled format, toprovide a second output including said digital content in the scrambledformat; outputting said first output including said digital content inthe descrambled format and the second output including said digitalcontent in the scrambled format; receiving a plurality of accessrequirements, wherein each access requirement can descramble the programdata; selecting at least one of the access requirements; storing thescrambled program data and the selected at least one access requirement.29. The copy management apparatus of claim 28, further comprisingreceiving and recording said digital content of said second output in ascrambled format.
 30. The copy management method of claim 28, furthercomprising: demultiplexing said digital content from said program data;and decompressing said digital content in a descrambled format to adecompressed state.
 31. The copy management method of claim 28, whereinsaid decompressing is executed in an MPEG decoder.
 32. The copymanagement method of claim 28, wherein said digital content is contentcontained in digital television transmissions.
 33. The copy managementapparatus of claim 28, wherein said digital content is contentdownloaded from the Internet.
 34. The copy management apparatus of claim28, wherein said descrambling is carried out in a first conditionalaccess unit.
 35. The copy management apparatus of claim 34, furthercomprising: retrieving the stored scrambled program data and the storedaccess requirement; descrambling the scrambled program using the accessrequirement in a second conditional access unit.
 36. The copy managementapparatus of claim 28, wherein said descrambling step comprises:extracting a descrambling key included in said program data; andapplying said descrambling key to said digital content in a scrambledformat to provide said digital content in a descrambled format.
 37. Acomputer readable medium containing instructions which, when executed bya processing system, cause the system to perform: receiving scrambleddata; receiving a first access key to descramble the scrambled data;receiving a second access key to descramble the scrambled data.
 38. Themedium of claim 37 wherein the first access key is associated with afirst conditional access unit.
 39. The medium of claim 38 wherein thesecond access key is associated with a second conditional access unit.40. The medium of claim 39 further comprising descrambling the scrambleddata using the first conditional access unit and the first key.
 41. Themedium of claim 40 further comprising recording the scrambled data andthe second access key in a computer readable memory.
 42. The medium ofclaim 41 further comprising retrieving the second access key and thescrambled data from the memory.
 43. The medium of claim 42 furthercomprising descrambling the scrambled data using the second conditionalaccess unit and the second access key.
 44. The medium of claim 43wherein the second access key permits the second conditional access unitto descramble the scrambled data during a time period including apresent time period and a future time period.
 45. The medium of claim 43wherein the first conditional access unit descrambles the scrambled dataduring a first period, and the second conditional access unitdescrambles the scrambled data during a second period that is differentfrom the first period.
 46. A computer readable medium containinginstructions which, when executed by a processing system, cause thesystem to perform a method for controlling the recording andreproduction of digital content comprising: receiving a digitalbitstream including program data, said program data including systeminformation and said digital content in a scrambled format; descramblingsaid digital content in a scrambled format to provide a first outputincluding said digital content in a descrambled format; providing asecond output including said digital content in the scrambled format;outputting said first output including said digital content in thedescrambled format and the second output including said digital contentin the scrambled format; receiving a plurality of access requirements,wherein each access requirement can descramble the program data;selecting at least one of the access requirements; storing the scrambledprogram data and the selected at least one access requirement.
 47. Themedium of claim 46, wherein the instructions, when executed by theprocessing system, further cause the system to perform receiving andrecording said digital content of said second output in a scrambledformat.
 48. The medium of claim 46, wherein the instructions, whenexecuted by the processing system, further cause the system to perform:demultiplexing said digital content from said program data; anddecompressing said digital content in a descrambled format to adecompressed state.
 49. The medium of claim 47, wherein saiddecompressing is executed in an MPEG decoder.
 50. The medium of claim46, wherein said digital content is content contained in digitaltelevision transmissions.
 51. The medium of claim 46, wherein saiddigital content is content downloaded from the Internet.
 52. The mediumof claim 46, wherein said descrambling is carried out in a firstconditional access unit.
 53. The medium of claim 52, wherein theinstructions, when executed by the processing system, further cause thesystem to perform: retrieving the stored scrambled program data and thestored access requirement; descrambling the scrambled program using theaccess requirement in a second conditional access unit.
 54. The mediumof claim 46, wherein said descrambling step comprises: extracting adescrambling key included in said program data; and applying saiddescrambling key to said digital content in a scrambled format toprovide said digital content in a descrambled format.
 55. An apparatuscomprising: means for receiving scrambled data; means for receiving afirst access key to descramble the scrambled data; means for receiving asecond access key to descramble the scrambled data.
 56. The apparatus ofclaim 55 wherein the first access key is associated with a firstconditional access unit.
 57. The apparatus of claim 56 wherein thesecond access key is associated with a second conditional access unit.58. The apparatus of claim 57 further comprising means for descramblingthe scrambled data using the first conditional access unit and the firstkey.
 59. The apparatus of claim 58 further comprising means forrecording the scrambled data and the second access key in a computerreadable memory.
 60. The apparatus of claim 59 further comprising meansfor retrieving the second access key and the scrambled data from thememory.
 61. The apparatus of claim 60 further comprising means fordescrambling the scrambled data using the second conditional access unitand the second access key.
 62. The apparatus of claim 61 wherein thesecond access key permits the second conditional access unit todescramble the scrambled data during a time period including a presenttime period and a future time period.
 63. The apparatus of claim 61wherein the first conditional access unit descrambles the scrambled dataduring a first period, and the second conditional access unitdescrambles the scrambled data during a second period that is differentfrom the first period.
 64. A copy management apparatus for controllingthe recording and reproduction of digital content comprising: means forreceiving a digital bitstream including program data, said program dataincluding system information and said digital content in a scrambledformat; means for descrambling said digital content in a scrambledformat to provide a first output including said digital content in adescrambled format; means for providing a second output including saiddigital content in the scrambled format; means for outputting said firstoutput including said digital content in the descrambled format and thesecond output including said digital content in the scrambled format;means for receiving a plurality of access requirements, wherein eachaccess requirement can descramble the program data; means for selectingat least one of the access requirements; means for storing the scrambledprogram data and the selected at least one access requirement.
 65. Thecopy management apparatus of claim 64, further comprising means forreceiving and recording said digital content of said second output in ascrambled format.
 66. The copy management apparatus of claim 64, furthercomprising: means for demultiplexing said digital content from saidprogram data; and means for decompressing said digital content in adescrambled format to a decompressed state.
 67. The copy managementapparatus of claim 64, wherein said decompressing is executed in an MPEGdecoder.
 68. The copy management apparatus of claim 64, wherein saiddigital content is content contained in digital televisiontransmissions.
 69. The copy management apparatus of claim 64, whereinsaid digital content is content downloaded from the Internet.
 70. Thecopy management apparatus of claim 64, wherein said descrambling iscarried out in a first conditional access unit.
 71. The copy managementapparatus of claim 70, further comprising: means for retrieving thestored scrambled program data and the stored access requirement; meansfor descrambling the scrambled program using the access requirement in asecond conditional access unit.
 72. The copy management apparatus ofclaim 64, wherein said means for descrambling comprises: means forextracting a descrambling key included in said program data; and meansfor applying said descrambling key to said digital content in ascrambled format to provide said digital content in a descrambledformat.